Biomedical subjects
Publications and source records attributed to S H Wakelin.
Pustular psoriasis is a rare but serious form of psoriasis. Clinically it may be difficult to differentiate from a pustular drug reaction. We report a case of a generalized pustular eruption triggered by exposure to amoxycillin in a patient with chronic psoriasis. Patch testing to 1% and 5% amoxycillin preparation confirmed a delayed hypersensitivity reaction.
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Livedoid vasculitis, otherwise known as segmental hyalinizing vasculitis or livedo reticularis with summer ulceration, is a chronic disease with lesions affecting the feet and lower legs. Early lesions show petechiae, but characteristic features are recurrent, bizarrely shaped ulcers that heal to leave hyperpigmentation and atrophie blanche. The aetiology of the disorder is unknown, but the histology shows fibrin deposition within both the wall and lumen of affected vessels. The absence of a sufficient perivascular infiltrate or leucocytoclasia argues against a vasculitis, being more in keeping with a thrombo-occlusive process. Four patients with livedoid vasculitis with ulceration are described, all of whom had associated raised anticardiolipin antibodies but no other evidence of systemic disease. We suggest that livedoid vasculitis may be a manifestation of the antiphospholipid syndrome and recommend that all patients are screened for this. We also discuss treatment options for this often resistant condition.
We describe a 37-year-old man who developed an acute, inflammatory flexural eruption shortly after taking amoxycillin, then erythema multiforme-like lesions on the palms and soles. The eruption resolved with systemic corticosteroids, and positive patch tests with amoxycillin supported a drug-induced aetiology. A few similar cases have been described as the 'baboon syndrome' or intertriginous drug eruptions. We draw attention to this rare, distinctive drug eruption.
Rubber is an important industrial and consumer product encountered in many household items and medical devices. Whereas the chemical additives used in its manufacture are well recognized as a cause of delayed-type hypersensitivity (allergic contact dermatitis), it is only during the past decade that immediate-type allergy to natural rubber latex (NRL) proteins (latex allergy) has emerged as a serious health issue. Frequent, prolonged wearing of NRL gloves, especially amongst health care workers, is a major risk factor for such sensitization. Latex allergy is now an important medical, occupational, medico-legal and financial problem, and it is essential that policies are developed to reduce it. Undiagnosed latex allergy is potentially very serious for patients. This article briefly overviews latex allergy with emphasis on the practical issues of diagnosis and management.
We report a case of systemic T-cell lymphoma with cutaneous lesions showing histological features of a cutaneous graft-versus-host-like-reaction. Histology from liver, lymph node and bone marrow showed a malignant T-cell infiltrate. T-cell receptor gene rearrangement studies confirmed the diagnosis. A cutaneous graft-versus-host-like reaction has been reported with disseminated malignancy and one case has been reported with systemic lymphoma. Graft-versus-host disease normally occurs when lymphocytes from an immunocompetent donor are introduced into a histo-incompatible recipient who is incapable of rejecting them. In our patient a similar reaction may have occurred if the lymphoma was composed of cytotoxic cells or if a cell-mediated immune response against the malignant T-cells cross-reacted with epidermal keratinocytes. Alternatively the malignant T-cells could have been functionally active and induced a lichenoid reaction in the skin.
Immediate-type hypersensitivity to natural rubber latex (NRL) may be associated with chronic eczema, and it has recently been suggested that NRL should be used as a patch-test allergen. However, a standardized preparation does not exist, and experience of patch testing with this substance is extremely limited. The aims of our study were to investigate the patch-test response to different preparations of NRL amongst patients with suspected contact dermatitis. 608 patients were patch tested with a latex series which included wet and dry preparations of undiluted high-ammonia (HA) NRL and low-ammonia thiuram-containing NRL. Cutaneous reactions to 1 or more NRL patches were noted in 24 patients. None of these were strong allergic reactions (> +), and in 15 patients, the responses were only doubtful (?+). Positive patch tests were observed in 9 patients, and were probably due to concurrent thiuram allergy in 6. In the remaining 3 patients, the reactions had subsided by the 2nd reading and may have represented false positives. None of the patients showed consistent allergic reactions to all NRL patches, and most of the doubtful readings had resolved within 4 days, suggesting that they were irritant rather than weak allergic responses. Patch testing to dry HA latex was associated with the least number of reactions. We conclude that allergic patch test reactions to NRL are uncommon, and as reactions are usually weak and difficult to interpret, we suggest that patch testing with NRL should remain experimental until further studies have been undertaken.
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We present the case of a 28-year-old woman with multiple familial trichoepitheliomas, characterized by the presence of many small tumors occurring predominantly on the face. This condition constitutes a genodermatosis that follows an autosomal dominant mode of inheritance. These lesions can lead to marked facial disfigurement, and treatment is generally disappointing.
Linear IgA disease (LAD) is characterized by circulating and tissue-bound IgA antibodies against heterogeneous antigens in the cutaneous basement membrane zone. In most cases the cause is unknown, but a minority of cases has been drug induced. We report a 76-year-old man who developed an acute blistering eruption following high-dose penicillin treatment for pneumococcal septicaemia. Indirect immunofluorescence demonstrated dermal binding IgA antibodies, and Western blotting of serum showed reactivity with a 250 kDa dermal antigen corresponding to collagen VII of anchoring fibrils. Indirect immunoelectron microscopy showed antibody labelling in the lamina densa and sublamina densa zone. This is one of the few cases of drug-induced LAD in which the target antigen profile has been characterized, and the first in which the antigen has been shown to correspond to collagen VII.
The subepidermal immunobullous diseases bullous pemphigoid (BP), cicatricial pemphigoid (CP), pemphigoid gestationis (PG) and linear IgA disease (LAD) are characterized by circulating and in vivo deposition of antibodies to antigens in the cutaneous basement membrane zone (BMZ). Indirect immunofluorescence (IMF) of serum is a routine diagnostic test to detect circulating BMZ antibodies in these diseases. We have compared the titres of IgG and IgA and their subclasses, also of IgM and IgE BMZ antibodies in serum and aspirated blister fluid in 35 adult patients with subepidermal immunobullous diseases: BP (n = 30), PG (n = 2), CP (n = 1), and LAD (n = 2), by indirect IMF on intact and salt-split skin. The antibody titre in blister fluid was the same or one dilution less than serum in most cases and there was no significant difference between these results (P > 0.05). IgG1 and IgG4 were the predominant subclasses in both blister fluid and serum in BP. Indirect IMF of serum and blister fluid was also carried out on trypsinized epidermal cells in a subgroup of patients with BP (n = 19). Typical polar fluorescence was obtained in all 14 cases which had positive indirect IMF on intact and split skin. Our findings demonstrate that blister fluid can be used as an alternative to serum for indirect IMF in subepidermal immunobullous diseases. This avoids the need for venesection and has a practical application in children and those with poor venous access.
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It has long been recognized that human skin can be subdivided into simple categories based on their sensitivity to sunlight--from Type I, never tans, always burns, to Type VI, marked constitutive pigmentation. There is also evidence that the more readily sunburnt type of skin is also more susceptible to the effect of irritants. In the present work, the irritancy threshold for sodium lauryl sulfate (SLS) has been assessed using a recently described 4-h acute skin irritation patch test. A total of 110 subjects covering all 6 skin types were examined and their threshold for acute irritancy defined as the lowest concentration of SLS, applied under 4-h occlusion, which would induce a clinically detectable irritant response. The SLS dose response generated using a range of concentrations (0.1%-20%) demonstrated that there was no significant difference between the groups under these test conditions. Even for Type VI skin (n = 25), the dose-response curve fell within the general pattern. These results reinforce the general applicability of predictions of acute irritant potential made in groups of human volunteers.